By Elise Foley

Huffington Post

WASHINGTON -- As Republicans threaten obstruction, lawsuits and even impeachment if the president acts on his own on immigration, Democrats urged him on Wednesday to make good on his promise to shield as many people as possible from deportation.

The Congressional Progressive Caucus, chaired by Reps. Raul Grijalva (D-Ariz.) and Keith Ellison (D-Minn.), sent a memo to President Barack Obama asking for swift and comprehensive executive action on immigration.

"Expansive and robust action that addresses the economic, family, community and national problems we now face is urgently needed," the memo reads. "Republicans in Congress have made it clear they will not engage in a good faith effort to fix our broken immigration system. The president has the legal authority and moral imperative to provide relief for over 7 million undocumented immigrants currently living in the shadows."

Obama promised earlier this year that he would take executive action on immigration -- which could include protecting millions from deportation -- between the elections and the end of the year. After major Democratic losses last week put the Senate in control of Republicans, Obama said his plans were unchanged. But Republicans have said repeatedly since that should Obama act on his own, he would "poison the well" for any immigration reform, and some advocates fear that the president could be persuaded to scale or delay his plans.

The Progressive Caucus memo calls for Obama to create a new program that would allow undocumented immigrants to apply for relief, similar to the Deferred Action for Childhood Arrivals policy, or DACA, that allows undocumented young people who came to the U.S. as children to stay and work legally. The Progressive Caucus said that program should be open to those who would be eligible for legal status under a Senate-passed immigration bill; immediate family members of citizens, green card holders and DACA recipients; undocumented immigrants who are "regularly employed," such as farm workers; and people who are ineligible for DACA but meet its education requirements. They also called for Obama to expand DACA to eliminate age limits, cut off dates and other barriers that prevent some undocumented immigrants who came to the country as children or teenagers from applying.

Also on Wednesday, a group of House Democrats and advocates gathered outside the Capitol to draw attention to how executive action could help members of the military and veterans whose families had been or could be torn apart be deportations.

"Mr. President, we ask you, please: You said you were going to do something. We beg you, do it now. There's urgency, and go big," Rep. Juan Vargas (D-Calif.) said. "And especially remember the military families, military families that have been divided because you haven't acted yet. Act now."

Elizabeth Perez, a military veteran whose husband was deported in 2010, gave an emotional plea for the president to allow already-separated families to be reunited in executive action. Perez said she served in the military for 10 years, including five in the Marine Corps, before marrying her husband and having two children. Her husband is now in Mexico and unable to return until at least 2020, she said.

"The president can do something. It's not just that the president can do something, he is the leader of our country," Perez said. "It's your obligation to do something. It's an obligation as a leader."

House Democratic Whip Steny Hoyer (D-Md.), who also appeared at the press conference to call for action, told reporters afterward that he hopes Republicans will pass immigration reform, and that executive action will not become an issue in funding the government.

"To say that if he does something that's within his power and that he believes is good for the country is going to therefore lead our Republican colleagues to not cooperate to make the country better and more economically secure, I think is not what the American people want," he said.